/*=============================================================================
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Copyright (c) 2003 Hartmut Kaiser
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http://spirit.sourceforge.net/
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Use, modification and distribution is subject to the Boost Software
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License, Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
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http://www.boost.org/LICENSE_1_0.txt)
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=============================================================================*/
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#ifndef BOOST_SPIRIT_SELECT_IPP
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#define BOOST_SPIRIT_SELECT_IPP
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#include <boost/spirit/home/classic/core/parser.hpp>
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#include <boost/spirit/home/classic/core/composite/composite.hpp>
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#include <boost/spirit/home/classic/meta/as_parser.hpp>
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///////////////////////////////////////////////////////////////////////////////
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namespace boost { namespace spirit {
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BOOST_SPIRIT_CLASSIC_NAMESPACE_BEGIN
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///////////////////////////////////////////////////////////////////////////////
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namespace impl {
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///////////////////////////////////////////////////////////////////////////////
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template <typename ParserT>
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struct as_embedded_parser : public as_parser<ParserT>
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{
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typedef typename as_parser<ParserT>::type::derived_t::embed_t type;
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};
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///////////////////////////////////////////////////////////////////////////////
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// no implementation here to catch unknown BehaviourT template arguments
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template <typename ResultT, typename BehaviourT>
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struct select_match_gen;
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// implementation for the select_default_no_fail behaviour
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template <typename ResultT>
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struct select_match_gen<ResultT, select_default_no_fail> {
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template <typename ScannerT>
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static ResultT
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do_ (ScannerT const &scan)
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{
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return scan.create_match(0, -1, scan.first, scan.first);
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}
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};
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// implementation for the select_default_fail behaviour
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template <typename ResultT>
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struct select_match_gen<ResultT, select_default_fail> {
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template <typename ScannerT>
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static ResultT
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do_ (ScannerT const &scan)
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{
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return scan.no_match();
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}
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};
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///////////////////////////////////////////////////////////////////////////////
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template <int N, typename ResultT, typename TupleT, typename BehaviourT>
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struct parse_tuple_element {
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BOOST_STATIC_CONSTANT(int, index = (TupleT::length - N));
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template <typename ScannerT>
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static ResultT
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do_(TupleT const &t, ScannerT const &scan)
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{
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typedef typename ::phoenix::tuple_element<index, TupleT>::type parser_t;
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typedef typename ScannerT::iterator_t iterator_t;
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typedef typename parser_result<parser_t, ScannerT>::type result_t;
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iterator_t save(scan.first);
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result_t result(t[::phoenix::tuple_index<index>()].parse(scan));
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if (result) {
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return scan.create_match(result.length(), TupleT::length - N,
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save, scan.first);
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}
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scan.first = save; // reset the input stream
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return parse_tuple_element<N-1, ResultT, TupleT, BehaviourT>::
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do_(t, scan);
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}
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};
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template <typename ResultT, typename TupleT, typename BehaviourT>
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struct parse_tuple_element<1, ResultT, TupleT, BehaviourT> {
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BOOST_STATIC_CONSTANT(int, index = (TupleT::length - 1));
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template <typename ScannerT>
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static ResultT
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do_(TupleT const &t, ScannerT const &scan)
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{
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typedef typename ::phoenix::tuple_element<index, TupleT>::type parser_t;
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typedef typename ScannerT::iterator_t iterator_t;
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typedef typename parser_result<parser_t, ScannerT>::type result_t;
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iterator_t save(scan.first);
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result_t result(t[::phoenix::tuple_index<index>()].parse(scan));
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if (result) {
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return scan.create_match(result.length(), TupleT::length - 1,
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save, scan.first);
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}
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scan.first = save; // reset the input stream
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return select_match_gen<ResultT, BehaviourT>::do_(scan);
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}
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};
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///////////////////////////////////////////////////////////////////////////////
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} // namespace impl
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BOOST_SPIRIT_CLASSIC_NAMESPACE_END
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}} // namespace boost::spirit
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#endif // BOOST_SPIRIT_SELECT_IPP
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